Conventional interfacing devices for transmission of duplex information allows for receipt of the information by full-duplex radios such as cellular phones. The increasing demand for installation of facsimile devices (which typically provide full-duplex information) in motor vehicles which have typical mobile radios may be precluded from receiving facsimile transmissions because their radio systems are not full duplex, but rather half-duplex or simplex. The previous solution to this problem would be to simply provide for a separate duplex radio or otherwise receive a non-standard simplex fax. Another solution includes using a non-standard fax machine that would have control lines linking with the interface device for controlling the receive and transmit mode. The present invention eliminates these restraints by providing an interface between the duplex signals of a standard telephone type FAX machine and a half-duplex radio.